Dir[File.dirname(__FILE__) + "/core_ext/*.rb"].sort.each do |path|
  filename = File.basename(path)
  require "active_support/core_ext/#{filename}"
end

# date,datetime,time这几个扩展是比较类似的,方法也不复杂,将不做注释
# core_ext里边最重要也是最复杂的几个扩展是object.rb,class.rb,module.rb
# 如果对metaprogamming有一定了解的话,对学习这几个扩展是有帮助的
# core_ext在很多地方作了兼容ruby1.9用法的改进
# changed by bonyfish choi on 2009-04-01
